lead free solder again

[Eeyore]

I am almost absolutely certain that avionics is in the exempt list.

I believe it's not actually *exempted* but doesn't fall into the RoHS remit !

Typical damn legalese nonsense. I suspect automotive gets off like that too (
covered by other legislation ). It's a totally ridiculous mire of paperwork
invented by the moronic fatheads in Brussels.

Graham

 

[vic]

I saw some pictures of those "tin whiskers", and I didn't know the
problem was so great.

http://en.wikipedia.org/wiki/Tin_whiskers

So... is Airbus required to go for lead-free solder too, for RoHS and
all that...?

Hoo-boy... if so, wouldn't want to fly on any Airbus aircraft built
after 2006, then...

Michael

So, does lead-free solder have this problem too ? How bad is it ? Do you
have studies, pictures, etc ?

vic

 

[Jon]

I saw some pictures of those "tin whiskers", and I didn't know the
problem was so great.

http://en.wikipedia.org/wiki/Tin_whiskers

So... is Airbus required to go for lead-free solder too, for RoHS and
all that...?

Hoo-boy... if so, wouldn't want to fly on any Airbus aircraft built
after 2006, then...

Michael

Michael,
(Slightly OT) It seems silly to spend so many resourses on ROHS with
respect to solder, when recycling would be a more sensible (and much
safer, as far as avionics is concerned) alternative. Think of all the
lead-acid automobile batteries that are in use. This lead is kept out
of the environment via recycling.
Regards,
Jon

 

[Eeyore]

So, does lead-free solder have this problem too ?

Too ? It is lead-free issues we're talking about !

How bad is it ? Do you have studies, pictures, etc ?

Just Google ! There are any number of problems with lead-free soldering notably,
in the consumer domain, reduced product lifetime resulting in more waste
generation.

Graham

 

[ian field]

Given the diameter of the whiskers, I doubt if they develop enough
force to punch through. Strange phenomena anyway, because the whiskers
don't start everywhere, but just here and there.



That's the one and only I heard off, and was mentioned here at
SED about a month ago? One case is not much. I don't hear Philips,
Sony, JVC, Samsung, HP, Canon, etc.


The list of exemptions can be widened, if need be. I can imagine
they add wrist watches to the list of exemptions, not much solder
in a wrist watch anyway, so who would care about that kind of
stuff being lead-free or not.

The big companies you mention are absolutely delighted that "through no
fault of their own" their products will have very short lifetimes, the
intermittent nature of lead free solder failure has created a consumer
mindset that once an item fails it will continue to give nothing but trouble
no matter how competently repaired, so most equipment is thrown out at the
first hint of intermittent operation!!!

 

[Eeyore]

The big companies you mention are absolutely delighted that "through no
fault of their own" their products will have very short lifetimes, the
intermittent nature of lead free solder failure has created a consumer
mindset that once an item fails it will continue to give nothing but trouble
no matter how competently repaired, so most equipment is thrown out at the
first hint of intermittent operation!!!

Which is of course about as *ungreen* as it gets despite the apparent motive
behind RoHS !

Graham

 

[ian field]

Which is of course about as *ungreen* as it gets despite the apparent
motive
behind RoHS !

Graham

The motive remains a mystery, I can see no advantage to the general
population!

 

[Joerg]

Hello Klaus,

Tin whiskers have nothing to do with lead-free or non lead-free parts.
It only depends on what kind of solder you are using.

I have just finished another design and several parts were only
available in non-lead. We used regular lead solder, no problem.

 

[nospam]

Hello Klaus,


I have just finished another design and several parts were only
available in non-lead. We used regular lead solder, no problem.

Yet....

The picture linked by the OP specifically shows whiskers growing on the tin
plated leads of a crystal in the area which had not been Sn/Pb solder
dipped.

--

 

[[email protected]]

Yet....

The picture linked by the OP specifically shows whiskers growing on the tin
plated leads of a crystal in the area which had not been Sn/Pb solder
dipped.

Found another reference, maybe this will help:

http://nepp.nasa.gov/whisker/background/index.htm

"What are Tin Whiskers?
Tin whiskers are electrically conductive, crystalline structures of tin
that sometimes grow from surfaces where tin (especially electroplated
tin) is used as a final finish."

Michael

 

[Joerg]

Yet....

The picture linked by the OP specifically shows whiskers growing on the tin
plated leads of a crystal in the area which had not been Sn/Pb solder
dipped.

Yes, it's a concern for all tin plated surfaces. Sometimes you can get
other plating but typically only on high-end parts. Ultimetaly time will
tell. If this RoHS and WEEE stuff turns out to be a major blunder, and
chances are that it does, we'll probably see a reversal in
manufacturer's reactions. To some extent we are already seeing that,
not in parts but in shipping policies. Don't know which one it was but I
have seen in the terms of one supplier that they simply will not ship
certain merchandise to Europe anymore.

 

[Frank Bemelman]

Which is of course about as *ungreen* as it gets despite the apparent motive
behind RoHS !

Somehow I just don't believe you're complaining because of the environmental
issues. Are you sure its got nothing to do with the hassles it gives, or
with
the fear for the unknown?

Let's see what happens. If it turns out as a disaster, nothing to worry.
We're all in the same boat. If it can't be solved, we'll be back to
leaded solder in notime.

BTW, I don't like lead-free either, it doesn't solder as nicely as the
good old leaded stuff. But it doesn't upset me, and my prototype stuff
and bench experiments don't suffer either.

 

[Eeyore]

Tin whiskers have nothing to do with lead-free or non lead-free parts.
It only depends on what kind of solder you are using.

That's wholly wrong. I was only reading recently about studies on whisker growth
on tin plated component leads.

I think it's accelerated by both high temperature and humidity btw.

Graham

 

[Joerg]

Hello Frank,

Somehow I just don't believe you're complaining because of the environmental
issues. Are you sure its got nothing to do with the hassles it gives, or
with
the fear for the unknown?

Ahem, couldn't it be the fear of the known? What telco companies found
out in the 40's can't simply be legislated away. Except that some
Eurocrats think they could. When you have a known problem and find a
solution (adding lead in this case) you typically don't go back to the
old stuff sixty years later without significant and proven mitigation.
Well, guess in Brussels they do that...

Let's see what happens. If it turns out as a disaster, nothing to worry.

With all due respect, I believe that position is a wee bit naive. Or
like they say in France, laissez faire. No worry, be happy, KABOOM.

We're all in the same boat. If it can't be solved, we'll be back to
leaded solder in notime.

And, of course, there will be no unintended consequences such as legacy
RoHS equipment that is going to be in use and where nobody knows when
and how spectacular the failure will be, will there?

BTW, I don't like lead-free either, it doesn't solder as nicely as the
good old leaded stuff. But it doesn't upset me, and my prototype stuff
and bench experiments don't suffer either.

Prototype stuff is fine. We'll all learn how to handle lead-free. The
problems may or may not surface after a few years. But when they do
surface, boy, I don't want to be the VP of Quality Control at one of the
manufacturers.

 

[Frank Bemelman]

Ahem, couldn't it be the fear of the known? What telco companies found
out in the 40's can't simply be legislated away. Except that some
Eurocrats think they could. When you have a known problem and find a
solution (adding lead in this case) you typically don't go back to the
old stuff sixty years later without significant and proven mitigation.
Well, guess in Brussels they do that...

Adding lead turned out to be a problem as well, so it was only
a half baked solution. Removing the lead in our car fuel was
not a bad idea. The 40% percent lead in solder is a *lot* and
seems worth looking into. Not at all costs/risks, so there are
a couple of exemptions already made.

With all due respect, I believe that position is a wee bit naive. Or
like they say in France, laissez faire. No worry, be happy, KABOOM.

Au contraire, the wasted lead is the ticking time bomb.

And, of course, there will be no unintended consequences such as legacy
RoHS equipment that is going to be in use and where nobody knows when
and how spectacular the failure will be, will there?

Ah, it *is* fear of the unknown

Prototype stuff is fine. We'll all learn how to handle lead-free. The
problems may or may not surface after a few years. But when they do
surface, boy, I don't want to be the VP of Quality Control at one of the
manufacturers.

All the VP's of QC are in the same boat as well. They all earn shitloads
of money and can retire at 40.

 

[Joerg]

Hello Frank,

Adding lead turned out to be a problem as well, so it was only
a half baked solution. Removing the lead in our car fuel was
not a bad idea. The 40% percent lead in solder is a *lot* and
seems worth looking into. Not at all costs/risks, so there are
a couple of exemptions already made.

Half baked? It worked. In cars it was easier, basically better valve
seats. My 1969 Citroen (engine designed in the late 30's or so) was
quite modern in that respect. It had no problems with unleaded.

Au contraire, the wasted lead is the ticking time bomb.

Nothing to worry? We'll watch that from a safe distance

Ah, it *is* fear of the unknown

Note that I didn't say "if" but "when" and "how spectacular". Just wait
until a couple of pins on the uC of a gas furnace controller let go
because the solder joints fouled up.

All the VP's of QC are in the same boat as well. They all earn shitloads
of money and can retire at 40.

Not around here, at least not for small companies. Small companies tend
to be less politically connected and that can burn then when RoHS does
backfire.

 

[Chris Jones]

Several product sectors have been exempted. Tells it all really.
http://www.pb-free.info/rohsexemptions.htm

If avionics aren't in there ( possibly covered by other legislation )
it'll be a worry given the high levels of vibration.

Some bright spark applied for an exemption for pro-audio ( no doubt on the
basis that ppl expect the stuff to last longer than 2-5 yrs ).

Shame that the video guys weren't so well on the ball !

Graham

Personally I would like to see a blanket exemption for any product which has
a warranty exceeding 10 years (probably with the companies contributing to
some kind of insurance scheme to ensure that the warranty will be honoured,
rather than giving an unfair advantage to companies that know in advance
that they don't intend to be around in 10 years' time).

People seem inclined to buy crap that is designed to fail in a few weeks
whether it's lead free or not. That kind of junk probably should be lead
free, (and people should have the brains not to buy it also) but if a
manufacturer makes a decent effort to build a reliable product and give a
good warranty then it makes sense to allow them to use the most reliable
materials particularly since it will in any case be mandatory to recycle
this stuff when it does need replacing.

Chris

 

[Roy L. Fuchs]

Tin whiskers have nothing to do with lead-free or non lead-free parts.
It only depends on what kind of solder you are using.

This is SO absolutely wrong.

 

[Robert Baer]

Didn't know that lead was added not until the late 40's.

But if you spray finished boards with some kind of coating,
would that not prevent the growth of whiskers?

** Maybe and maybe not. Results are highly variable.
Try something and i might work and someone else might have problems.
Absolutely guaranteed to be variable.

 

[Klaus Bahner]

unless the aerospace manufacturers have hangers full of leaded parts,

That's wholly wrong. I was only reading recently about studies on whisker growth
on tin plated component leads.

Ok, I should have been more precise. Even if there are only lead free
parts available you are still able to process them in a non-lead-free
process, which means you can easily coat your parts with a lead/tin
alloy. Comes automatically when you reflow SMD components with lead/tin
alloy, leaded parts may require special handling, if you mount them with
largely exposed leads - but standoffs might be anyway a good idea in
such a situation. The popular picture of the tin whisker on the crystal
lead shows a crystal with a rather unintelligent mounting position
anyway. Avoiding mechanical stress, i.e. bending, shouldn't be a big
deal if you adapt your production to a lead free process.

Besides that I just don't think it's appropiate to call RoHS for the
doomsday of all electronics. So far, the incidents on NASA's popular tin
whisker site seem rather exotic to me (a satellite for example is
working under ultra high vacuum, extreme temperature and high radiation
conditions). I don't know whether RoHS will be a more complex problem
than adapting to other production issues. So far I think chances are
rather high that you can control it in the same way as other production
issues. (How many failures of end products were caused because
production plants didn't stick to the correct soldering temperature
profile or didn't bake components correctly?)


Klaus